Slush pump piston



March 14, 1961 J. 5. BECK SLUSH PUMP PISTON 2 Sheets-Sheet 1 Filed Nov. 6, 1959 JUL/US S. BECK ATTORNEY J. S. BECK SLUSH PUMP PISTON March 14, 1961 2 Sheets-Sheet 2 Filed Nov. 6, 1959 FIG. 9.

FIG. 6.

JUL/US S. BECK ATTORNEY Un fie S ates.

SLUSH PUMP PISTON Julius S. Beck, 2785 Cherry Ave., Long Beach 6, Calif. Filed Nov. 6, 1959', Ser. No. 851,392 5 Claims. 01. 309-4 This invention relates to pumps such as those. for circulating drilling fluid when drilling oil and gas wells. Particularly, the invention is directed to an improved piston having replaceable and interchangeable rubbers. As herein used, the word rubbers has reference to resilient cylindrical members mounted on reciprocating Patented Mar. 14, 1961 rubbers.

bodies or cores and in sliding contact with pump cylinder liners. Preferably, the rubbers of the invention are made of Teflon, but may be made of other suitable material such as neoprene or nylon.

, Heretofore, piston rubbers were vulcanized or similarly bonded, at least in part, on the piston cores, but

' Figure 8 is an enlarged perspective View of a portion of the core, one of the rubbers and a sectional portion of the lubricant dispensing ring.

Figure 9 is an enlarged longitudinal sectional view of a typical lubrication fitting such as mounted in one end of the piston core, and

Figure 10 is a broken sectional view of a portion of a slush pump and showing the present piston forming a part thereof, together with means lubricating the piston without removing the cylinder head.

The portion of a slush pump 10 shown in Figure 10 includes a cylinder 11, a liner 12, a piston rod 13 and cylinder head 14, all in the usual manner. The cylinder head 14 includes an asymmetrically located tapped hole 15 for inserting the neck of a lubricating gun 16 for connection with a fitting to be described. A thread did not always adhere because they were subjected to considerable tension and compression forces. Additionally, the referred to bonds were, at times, subjected to acid when acidizing 'a well, and which 'aci'd'l 1ad' a deteriorating effect on the bonds. Because the rubbers were subjected to the abrasives suspended in the'drilling fluid a lubricant was required, and this was accomplished by impregnating the rubbers with graphite. However, the presence of graphite in the rubber reduced the tensile strength and subjected the rubbers to breakage.

Another problem in prior constructionshad to do with wear of cylinder liners. The abrasive action of drilling fluids makes the use of replaceable liners necessary, but new liners are not always readily available in the field. Moreover, the inside diameters of liners vary and liners having the required piston dimensions were sometimes diflicult to obtain.

An object of the invention is to provide a piston of the described class which is durable and not subject to breakage or failure in its use. p

Another object is to provide a slush pump piston capable of convenient replacement of rubbers in the field.

Another object is to provide a slush pump piston wherein the body or core will not be damaged in the event of rubber failure.

A further object is to provide a slush pump piston.

which may be lubricated without removing the cylinder head. Y

A particular object is to provide a-threadJike lead construction and assembly for retaining the rubbers on the core, and which lead-includesboth left and right hand threads for reducing torque loads about the piston rod axis.

These and other objects will become apparent from the following description and accompanying drawings, wherein:

Figure 1 is a sectional view taken along the axis of a piston embodying the features of the invention.

Figure 2 is a reduced scale side elevational view of the piston shown in Figure 1.

Figure 3 is an end elevation showing the core, rubber, retainer and lubricating fitting.

Figure 4 is a reduced scale perspective view of the lubricant dispensing ring.

Figure 5 is an enlarged broken sectional view of the ed plug, not shown, is secured in the tapped hole 15 when the pump is in operation.

Referring now to Figure 1, the piston comprising the invention includes a tubular core 17 having a tapered axial opening 18 of standard size for engagement on a conventional piston rod, such as 13. The outer center surface of thecore 17 is cylindrical, as at 19, for slidably receiving a, lubricant dispensing ring, generally desigi nated by the numeral 20, and hereinafter referred to in detail.

Adjacent the cylindrical surface 19 there are outwardj 1y projecting integral thread-like leads 21 for retaining an inner piston rubber 22, and similarly there is a threadlike lead 23 on the opposite side of the core surface 19 for engaging an outer piston rubber 24. The lastreferred to lead 23 is removably mounted on the core 17 by means of threads 25. The threads of the leads 21 and 23 are oppositely turned, that is, right hand and left hand, and which threads are of a buttress type, namely, substantially perpendicular on one side and downwardly inclined toward their respective ends of the core 17.

Between the first described lead 21 and the adjacent end of the core 17 there are threads 26 for receiving an angularly and inwardly flanged retainer 27 for engag: ing'an inner circular portion 28 of the outer face, of the first referred to rubber 22. The inner circular por; tion 28 is angular in cross section to correspond with the angular flanged portion, not numbered, of the rctainer 27. A flanged retainer 29, identical with the first described retainer 27, is mounted on the first described threads 25 for engaging the inner circular portion of the outer rubber 24. The flanges of the retainers may be provided with set screws 30 for engaging the rubbers 22 and24 and thereby preventing the retainers from be coming-unscrewed.

In cross section, the lubricant dispensing ring 20 is divergingly tapered from the approximate centers of side faces, the angles of which are herein referred to by the numeral 31 where the same extend to the inner angles in the direction of the piston Normally, the

adjacent peripheries or lips 35 and 36 of the rubbers 22 and 24 are spaced from the ring 34 and are spaced from the shoulder 33.

The inner diameter of the lubricant dispensing ring 20 is provided with a circular chamber 37 whichcommunicates with a circular groove 38 in the cores cylindrical surface 19. Radial passages 39 extend from the circular chamber 37 to the shoulders 33, and other radial passages 40 extend from the same chamber to a groove 41 around the ring 34. Longitudinal bores 42 in the core 17 extend from the outer or cylinder head end thereof to the circular grove 38. The upper bore 42 is provided with a check-type lubrication fitting 43, such as shown in Figure 9, whereas the remaining bores have threaded plugs 44 in their outer ends. It is to be understood that the installation of the piston in the cylinder 11 may have any of the longitudinal bores at the top of the piston; thus, the plugs 44 and fitting 43 may be interchanged so that the latter is at the top and at least generally opposite the tapped hole 15 in the cylinder head 14.

In operation, the rubbers 22 and 24 are securely held on the core 17 by means of the leads 21 and 23 and the retainers 27 and 29. A suitable lubricant may be conveniently applied under pressure through the tapped hole 15 in the cylinder head 14 in the manner described and illustrated in connection with Figure 10. It is pointed out that the lubricant, under pressure, is transmitted from the fitting 43, through its longitudinal bore 42 to the core groove 38, thence into the ring chamber 37 and outwardly through radial passages 39 and 40, thus assuring lubrication without impregnating the rubber material. The rubbers 22 and 24 may be conveniently replaced in the field by removing the piston from the rod 13, unscrewing the retainers 27 and 29 and unscrewing the. rubbers 22 and 24 from their respective leads 21 and 23. Within the spirit of the invention, it is contemplatedthat a single core 17 will be provided with several sets of rubbers and lubricant dispensing rings to fit various inside diameters of cylinder liners 12.

The invention is not limited to the exemplary construction herein shown and described, but may be made in many ways within the scope of the appended claims.

What is claimed is:

1. A piston comprising a tubular core, a ring around said core intermediate the ends thereof, said core having a cylindrical surface therearound and on which said ring is detachably mounted, threaded leads around said core on opposite sides of said ring, cylindrical rubbershaving internal threads threadedly engaged on said leads, the diameters of said rubbers being at least equal to the.out side diameter of said ring, one of said threaded leads being threadedly mounted on said core adjacent said cylindrical surface on which said ring is mounted, and retainers demountably engaged on said core outwardly of said leads and engaging the inner surface portions of the outer ends of said rubbers.

2. A piston comprising a tubular core, a ring around said core intermediate the ends thereof, said ring including a circular chamber therein and including radial passages outwardly thereof, means in said core supplying a lubricant to said chamber and passages, said means including a check-type fitting in one end of said core, said core having a cylindrical surface therearound and on which said ring is detachably mounted, threaded leads around said core on opposite sides of said ring, cylindrical rubbers having internal threads threadedly engaged on said leads, the outside diameters of said rubbers being at least equal to the outside diameter of said ring, one of said threaded leads beingthreadedly mounted on said core adjacent said cylindrical surface on which said ring is mounted, and retainers demountably engaged on said core outwardly of said leads and engaging the inner surface portions of the outer ends of said rubbers.

3. A piston comprising a tubular core, a ring around said core intermediate the ends thereof, said core having a cylindrical surface therearound and on which said ring is detachably mounted, threaded leads around said core on opposite sides of said ring, the threads of one said lead being spiraled in a direction opposite to the threads of the other said lead, cylindrical rubbers having internal threads threadedly engaged on said leads, the outside diameters of said rubbers being at least equal to the outside diameter of said ring, one of said threaded leads being threadedly mounted on said core adjacent said cylindrical surface on which said ring is mounted, and retainers demountably engaged on said core outwardly of said leads and engaging the inner surface portions of the outer ends of said rubbers.

4. A piston comprised of a tubular core, a laterally projecting ring around said core intermediate the ends thereof, retainers demountably secured on the ends of said, core, cylindrical rubbers mounted on said core between said ring and said retainers, said ring including radial passages therein and extending outwardly thereof, and means supplying a lubricant to said passages, said means including a check type fitting in one end of said core.

5. A piston rod comprising a tubular core, a. cylindrical surface around the center of the said core, a lubricant dispensing ring around said core and detachably mounted on said cylindrical surface, threaded leads around said core on opposite sides of said ring, cylindrical rubbers having internal threads threadedly engaged on said leads, said internal threadsin said rubbers and the spirals of said leads are in opposite directions on opposite sides of said ring, the outside diameters of said rubbersbeing at least equal to the outside diameter of said ring, retainers demountably engaged on said core outwardly of. said leads and engaging the inner surface portions of the outer end of said rubbers, said lubricantring including a circular. chamber therein and including radial passages outwardly thereof, and means applying a lubricant to said chamber and passages, said means including a check type fitting in one end of said core.

References Cited in the file of this patent UNITED STATES PATENTS 1,927,460 Leman Sept. 19, 1933 2,063,724 Cater Dec. 8, 1936 2,599,082 Wells June 3, 1952 2,748,718 MacClatchie June 5, 1956 

